Adapter to permit the burning of lpg fuels in normally liquid-fuel burning stoves



Dec. 27, 1966 R. R. THOMPSON 3,

ADAPTER TO PERMIT THE BURNING OF LPG FUELS IN NQRMALLY LIQUID-FUELBURNING STOVES Filed June '7, 1965 R/CHARD R. THOMPSON lA/VE/VTUR BY 59BUCKHOEW, BLORE, KLAROU/ST a SPAR/(MAN nited States Patent Gfifice3,294,079 Patented Dec. 27, 1966 3,294,079 ADAPTER T PERMIT THE BURNING0F LPG FUEFE IN NQRMALLY LlQUlD-FUEL BURNING STOVES Richard R. Thompson,Rte. 2, Box 55, Oregon City, Greg. 97405 Filed June 7, 1965, Ser. No.461,781 7 Claims. (Ql. 12638) The present invention relates to liquidpetroleum gasburning stoves and more particularly to an adapter whichpermits the burning of liquid petroleum gas fuels such as propane andbutane in normally liquid-fuel burning camp stoves and the like.

Camp stoves have become an almost indispensable item for campers, andmost camp stoves are designed to burn gasoline or other liquid fuels.However, such liquid-fuel burning stoves have several annoyingdisadvantages, probably the most annoying of which are theall-toofrequent pumping of air into the fuel tank required to maintain adesired heat and flame and the frequent refilling of the fuel tankrequired. Spillage of fuel during refilling is difficult to avoid, andconsequently fuel odors are usually present while such stoves are inuse. In addition, carbon tends to collect at certain points in the fueldistribution systems of gasoline stoves so as to require cleaning fromtime to time to keep them working properly, and carbon also collects onutensils exposed to their flame.

Liquid petroleum gas (LPG) has numerous advantages over gasoline andother liquids as fuel for camp stoves, among which are its cleanness,low cost, hotter flame and constant heat. LPG fuels are convenientlystored in refillable tanks in pressurized liquid form so that spillageis no problem.

Accordingly, a primary object of the present invention is to provide anew and improved method of adapting a normally liquid-fuel burning stovefor burning LPG fuels.

Another primary object is to provide a novel device for converting anormally liquid-fuel burning stove to one for burning LPG fuels.

A more specific object is to provide a conversion device which quicklyand easily adapts a conventional gasolineburning camp stove for burningLPG fuels.

A further object is to provide a novel device as described which issimple to construct, install and operate.

Sitll another object is to provide a device as described which is onlytemporary and which enables the stove to be converted back to itsoriginal gasoline-burning condition rapidly and easily.

Another object is to provide a device as described which is compact,portable and easily removable from the stove for storage in transit.

Another object is to provide a device as described which is constructedof a relatively few number of inexpensive parts and which utilizes mostof the original parts of the stove.

The above and other objects and advantages will become more apparentfrom the following detailed description which proceeds with reference tothe accompanying drawing wherein:

FIG. 1 is a perspective view of a gasoline camp stove with a conversiondevice in accordance with the invention attached thereto;

FIG. 2 is an enlarged view of the conversion device of FIG. 1, partly insection;

FIG. 3 is a view on a slightly larger scale than FIG; 1 illustrating aconventional gasoline supply tank supplied 7 as an original part of thecamp stove and the valve and generator assembly connected thereto;

FIG. 4 is a fragmentary perspective view, on an enlarged scale, showinga portion of the camp stove of FIG. 1 and a portion of the conversiondevice attached thereto in its operative position;

FIG. 5 is a perspective view on a greatly enlarged scale showing aleveling block which forms a portion of the conversion device.

With reference to the drawings, FIG. 1 illustrates a conventionalgasoline-burning camp stove 10 of the Coleman type mounted on a stand 12and including a sheet metal base portion 14 in which a pair of burners15 are provided, and a cover 16 which serves as a windshield whenupright as shown. A gasoline tank 17 and connected valve and generatorassembly 18 (FIG. 3) are normally mounted on the outside front wall 19of the stove, but when burning LPG fuel, such tank is removed from thestove and replaced with the conversion device of the present inventionshown generally at 20 connected to a tank, or cylinder, 21?. of liquidpetroleum gas (LPG) fuel stored under high pressure in liquid form.

The conversion device is shown in greater detail in FIG. 2 and includesas its principal parts an adjustable diaphragm-type pressure regulator,or reducing valve, 24, a length of flexible hoseio, a shut-off valve 28and an elongate, hollow rigid tube 3t having a small discharge orifice32 at its terminal end. The tube 3t) is in actuality the generator tubeprovided with the usual gasoline stove as a part of the needle valve andgenerator assembly 18 to transfer the fuel from the tank 17 to the mainburner 15, with the exception that the usual needle valve assembly 33and encircling coil 34 have been removed from the interior of the tubeas shown in FIG. 3.

Threaded onto the end of the generator tube opposite the orifice 32 isan elongate coupling 36 connecting the tube to the outlet end of ahousing 38 for shut-off valve 28. The shut-off valve 2% is of aconventional needle type, and is opened and closed by means of a handle39. The inlet end of the shut-off valve housing is threadedly connectedby a coupling 49 to one end of a hose fitting 41 on the flexible hose26, and the opposite end of the hose is threadedly connected by anotherhose fitting 42 to the outlet end of a housing 44 for the reducing valve24. The reducing is of a well-known construction and includes a threadedadjustment member 46 for regulating the valve for the amount of pressurereduction desired. The inlet end of the reducing valve housing isthreadedly connected to a fitting 48 which includes a threaded sleevecoupling 49 slidable on the fitting for threadedly attaching thereducing valve-end of the conversion device to the upper end of the LPGfuel tank 22 at the shut-off valve for the tank.

In addition to the foregoing elements, the device includes as animportant feature a means in the form of a spring clip 50 for rigidlybut releasably attaching the tube 39 and shut-off valve to the campstove. The spring clip includes a ring 52 which encircles the valvehousing 38 in an annular depression 53 created at the juncture betweenthe housing 38 and the elongate coupling 36 joining the housing to thegenerator tube. The ring is sufliciently small in diameter so that itcannot slip over the coupling and cannot be removed from the devicewithout unthreading the coupling from the valve housing. However, thering is sufficiently large so that it can swivel in the groove 53. Thering has an eye 54 to which is connected one end of a relatively longcoil spring 55. The opposite end of the spring is connected to one endof a clip 58 having a hook 59 at its other end.

With reference to FIG. 4, the tube 30 extends into the 0 camp stovethrough the usual opening 60 in the front face usual manner. A levelingblock 64 having a slot 66 in one side, as clearly shown in FIG. 5, isplaced in the opening 60 with the bottom edge of the opening extendinginto the slot. The rear end of the tube rests on the upper surface ofthe block to level the same. The spring clip 50 is hooked on an edge ofone of the vent openings 68 provided in the bottom of the stove tostabilize the tube and shut-off valve.

To convert the gasoline camp stove shown for use with LPG fuel, thegasoline tank 17 is first removed from the stove and the generator tube30 unscrewed from the valve fitting 18 on the top of the tank. Then theneedle assembly 33 and coil 34 surrounding the assembly are removed fromwithin the tube, and any existing carbon is cleaned from the tube andits orifice 32. Following this, the generator tube is threaded into theend of the coupling 36 of the convention device, which is preassembledin the form shown in FIG. 2.

With the generator tube now forming a portion of the conversion device,the leveling block 64 is placed in the front opening 60 of the campstove, and the generator tube is inserted through the opening and intothe fuel inlet opening 62 of the main burner. The spring clip is thenhooked to the underside of the stove to place the spring 56 in tensionand thereby affix the tube and valve housing rigidly to the stove.Following this, the fitting 48 at the regulator end of the conversiondevice is connected to the standard valve fitting 7 provided at theupper end of the cylinder 22 of LPG fuel by tightening the sleevecoupling 49.

With the device now attached to both the stove and to the LPG fuelsupply, the valve 70 on the cylinder is opened to force fuel through thedevice down to the shutoff valve 28.

Thereafter a burning match is placed adjacent the master burner 15 andthe handle of the shut-off valve turned to open the valve, thus sendingfuel to the main burner and igniting the same instantly. The height ofthe flame at the main burner can be controlled by opening or closing theshut-off valve slightly to control the flow of gas. The stoves otherburner can then be ignited by opening the individual control valve 72therefor and igniting it with a match in the usual manner.

With the device as described, a gasoline camp stove can be quickly andeasily adapted for burning LPG fuel and conversely, the stove can beconverted back to use as an ordinary gasoline stove simply by removingthe generator tube from the conversion device, reinserting the needlevalve assembly 33 and coil 34 into the tube, reattaching the tube to thevalve fitting 18 on the tank, and thereafter attaching the tank 18 tothe stove in the usual manner.

It has been found that my conversion device works best when the pressureregulator is adjusted to deliver an outlet pressure of from to 35 poundsper square inch. I have also found it preferable to provide all-brassfittings and to seal the same with a heavy-duty acryli or equivalentcoating to preserve the finish and weatherproof the device. With mydevice I have been able to operate an ordinary gasoline camp stove forforty hours or more with one gallon of LPG fuel costing less than fiftycents.

Having illustrated and described a preferred embodiment of my invention,it should be apparent to those skilled in the art that the inventionpermits of modification in arrangement and detail. In any event, it isto be understood that my invention is not to be limited other than bythe following claims.

I claim:

1. A conversion apparatus for use in combination with a liquid-fuelburning stove for converting said stove to use with liquid petroleum gasfuels, said stove normally including a burner with a fuel inlet and agenerator tube connected to a liquid fuel tank and having a rod and coilwithin said tube, said apparatus comprising:

a length of flexible hose,

a reduction valve means connected to one end of said hose,

connector means adapted for connecting said reduction valve means to apressurized supply of liquid petroleum gas fuel,

a shut-off valve means connected to the other end of said hose,

said shut-off valve means including a housing provided with a connectormeans adapted for connecting said housing to the generator tube of theliquid-fuel burning stove after the tube has been disconnected from itsfuel tank and after the rod and coil have been removed from within saidtube,

and releasable attachment means adapted for rigidly attaching saidshut-off valve housing to the stove with said shut-off valve positionedoutwardly of and adjacent said stove.

2. A conversion apparatus according to claim 11 wherein said attachmentmeans includes a leveling block adapted for supporting one end of saidgenerator tube at a sidewall opening in said stove, said block memberincluding a slot therein for retaining said block on the bottom edge ofsaid opening, and spring clip means connected at one to said housing andhaving a free end adapted to hook onto said stove.

3. A conversion apparatus according to claim 1 wherein said attachmentmeans includes a resilient means attached to said housing and a hookmember attached to said resilent means.

4. In combination with a gasoline-burning camp stove having a mainburner, a fuel inlet opening for said burner, a base having a sidewallaccess opening into the interior of said base and a bottom vent opening,and a generator tube for transmitting a mixture of air and gasoline tosaid main burner, said tube being threaded at one end and having adischarge orifice at the other end,

a device for adapting said stove for burning liquid petroleum gas fuelcomprising:

needle-type shut-off valve means, including a valve housing threadedlyconnected to the threaded end of said generator tube,

adjustable gas pressure regulating means,

a length of flexible hose connecting said regulator means and saidshut-off valve means,

a tank of pressurized liquid petroleum gas fuel,

connector means connecting said regulator means to said tank,

and attaching means including a resilient means connected to saidhousing and a hook means connected to said resilient means at one endand hooked to an edge of said vent opening for rigidly attaching saidgenerator tube and housing to said stove when said tube is insertedthrough said access opening and into said fuel inlet openmg.

5. The method of converting a normally gasolineburning camp stove to onefor burning liquid petroleum gas fuels, said stove having a base, a mainburner in said base including a fuel inlet opening, a front accessopening in said base, a gasoline supply tank, a generator assemblyconnected to said tank including a generator tube, and a needle assemblyand coil within said tube,

said method comprising the steps:

removing said gasoline tank from said stove,

removing said generator tube from said tank,

removing said needle assembly and said coil from said generator tube,

inserting said tube through said front access opening and into said fuelinlet opening,

connecting said tube to a supply of pressurized liquid petroleum gasfuel,

controlling the flow of said liquid petroleum gas into said tube byreducing the pressure of the same between said supply and said tube suchthat the same is discharged from said tube and into said main burner ina gas state.

6. In combination with a gasoline-burning cam-p stove having a burnerwith a fuel inlet opening, a conversion device for converting said stovefor use with liquid petroleum gas fuels,

said device comprising in combination:

an elongate rigid metal tube having a discharge orifice at one end and athreaded opposite end,

said tube having a length sutficient to extend from the front of saidstove to said fuel inlet opening,

shut-off valve means including a shut-01f valve housing threadedlyconnected at its outlet end to the threaded end of said tube,

means On said housing for rigidly and removably attaching said housingto said stove with the discharge orifice end of said tube inserted insaid fuel inlet opening,

a length of flexible hose connected at one end to the inlet end of saidhousing,

pressure-regulating valve means including a regulator housing connectedat its outlet end to the other end of said hose,

and threaded coupling means connected to the inlet end of said regulatorhousing for threadedly connecting said regulator means to a tank ofpressurized liquid petroleum gas fuel.

7. In combination with a gasoline-burning camp stove having a burnerwith a fuel inlet opening, a stove housing having an access openingtherein into the interior of said housing, and a fuel-vaporizing tubeincluding a rod and coil within said tube, said tube having an orificeat one end and being threaded at the opposite end thereof,

a device for adapting said gasoline-burning camp stove for burningliquid petroleum gas fuel comprising:

storage means for storing a pressurized supply of liquid petroleum gasfuel,

flexible conduit means extending between said storage means and saidfuel-vaporizing tube,

first connector means carried by one end of said flexible conduit meansfor threadly connecting said one end to said storage means,

second connector means carried by the opposite end of said flexibleconduit means for threadedly connecting said opposite end to saidfuel-vaporizing tube after said rod and said coil have been removed fromsaid tube,

pressure-reducing valve means connected to said flexible conduit meansbetween said first and second connector means,

flow control and shut-ofi valve means connected to said flexible conduitmeans between said first and second connector means,

and attaching and stabilizing means for removably connecting saidflexible conduit means and its connected elements to said stove housingand for stabilizing said fuel-vaporizing tube in its operative positionwithin said housing.

References Cited by the Examiner UNITED STATES PATENTS CHARLES J.MY'HRE, Primary Examiner,

1. A CONVERSION APPARATUS FOR USE IN COMBINATION WITH A LIQUID-FUELBURNING STOVE FOR CONVERTING SAID STOVE TO USE WITH LIQUID PETROLEUM GASFUELS, SAID STOVE NORMALLY INCLUDING A BURNER WITH A FUEL INLET AND AGENERATOR TUBE CONNECTED TO A LIQUID FUEL TANK AND HAVING A ROD AND COILWITHIN SAID TUBE, SAD APPARATUS COMPRISING: A LENGTH OF FLEXIBLE HOSE, AREDUCTION VALVE MEANS CONNECTED TO ONE END OF SAID HOSE, CONNECTOR MEANSADAPTED FOR CONNECTING SAID REDUCTION VALVE MEANS TO A PRESSURIZEDSUPPLY OF LIQUID PETROLEUM GAS FEUL, A SHUT-OFF VALVE MEANS CONNECTED TOTHE OTHER END OF SAID HOSE, SAID SHUT-OFF VALVE MEANS INCLUDING AHOUSING PROVIDED WITH A CONNECTOR MEANS ADAPTED FOR CONNECTING SAIDHOUSING TO THE GENERATOR TUBE OF THE LIQUID-FUEL BURNING STOVE AFTER THETUBE HAS BEEN DISCONNECTED FROM